The organization "C02 is Green" funded a half-page advertisement in The Washington Post urging people to call their senators and seek a vote against "the president's cap-and-trade bill that will increase your cost of living and not change the climate.

"The bill is based on the false premise that man-made CO2 is a major cause of climate change," the ad says. "Real, empirical evidence indicates it is not."

The ad makes a number of other charges, including that the bill from Sens. John Kerry (D-Mass.) and Joe Lieberman (I-Conn.) will drive up prices for electricity, transportation fuel and food, that the country relies on fossil fuels and that the backers of the bill are "buying support from industries on Wall Street with various corporate giveaways."

CO2 is Green spokesman H. Leighton Steward sits on the board of directors of EOG Resources Inc., an oil and natural gas development company. He also is an honorary director at the industry trade group American Petroleum Institute, according to a biography on EOG's website.

The intent of the ad is more political than scientific, said Ken Green, resident scholar at the American Enterprise Institute think tank.

"The purpose of their ad is obviously to try to show the Democrats there's a large body of people who do not want climate controls and will punish them in the midterm elections," Green said.

But David Di Martino, spokesman for Clean Energy Works, a coalition of about 60 groups that want climate legislation, maintains the ads cannot be taken seriously.

"The ad reads like the 'climate deniers' manifesto,'" Di Martino said. "This Big Oil front group wants people to think Congress is going to raise taxes, kill jobs, spill more oil, take our children and charge us for the pleasure."

The ad, Di Martino said, is "funded by the world's largest polluters and those who stand to profit from our continued dependence on fossil fuels for our energy." In addition to Steward, he said, CO2 is Green is bankrolled by Corbin J. Robinson, chief executive of and leading shareholder in Natural Resource Partners, a Houston-based owner of coal resources.

"Considering the source, the message of the ad, and the intent to keep America addicted to oil, this cynical front group should change its name to 'Greed is Good,'" Di Martino said. He added that the bill from Kerry and Lieberman "is projected by independent studies to create new American jobs and it will reduce our deficit by $20 billion," according to figures from CBO.

Statements made in the ad about climate change are "patently false," Di Martino said.

The Intergovernmental Panel on Climate Change in its 2007 report declared evidence of global warming to be "unequivocal" and pinned much of the blame on human activities.

The Climate Interactive Scoreboard earlier this month calculated that despite recent pledges by 60 countries to reduce carbon emissions, in 2100 the world will end up with temperature increases of 4 degrees Celsius.

Claims made in the new ad need to be parsed, Green said. All temperature increase estimates, he said, "are based on assumptions about how sensitive the climate is to added greenhouse gases." The IPCC, and much of the climate "establishment" uses high estimates of sensitivity, which leads to predictions of severe temperature increase. Others disagree with the IPCC's sensitivity estimate."

Some scientists argue, Green said, that a temperature increase of 1 degree is more likely and that given that, "greenhouse gases are not that potent. That doesn't mean it's green. Those are two different things. Yes, it's true increased CO2 means increased plant growth," Green said, but there are unknown environmental damages and questions about ocean acidification.

"People who make claims like [CO2 being green] are being just as irrational as people saying it's going to destroy the Earth," he added. "No one has enough info to actually say that."

The ad also charges that "Even if CO2 was a major factor," using the IPCC's own formula and numbers, "the bill would only reduce Earth's temperature by one tenth of one degree within the next 90 years."

The claim that policies proposed in current legislation won't have much effect on climate have some validity, Green said. Environmental groups, he said, argue that those changes would be a start toward addressing carbon emissions and climate change.